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Chingis M. Nigmatullin - One of the best experts on this subject based on the ideXlab platform.

  • Age, growth and reproductive biology of diamond-shaped squid Thysanoteuthis Rhombus (Oegopsida : Thysanoteuthidae)
    Marine Ecology Progress Series, 1995
    Co-Authors: Chingis M. Nigmatullin, Alexander I. Arkhipkin
    Abstract:

    Age and growth of the large oceanic squid Thysanoteuthis Rhombus were estimated by statolith increment analysis of 72 specimens [mantle length (ML) ranging from 25 to 805 mm] and reproductive biology was studied on 162 T. Rhombus (ML 150 to 850 mm) captured in the eastern tropical Atlantic and southwestern Pacific between 1976 and 1990. The maximum ages found in our samples were observed in a mature female of 750 mm ML (305 d) and in a mature male of 770 mm ML (309 d). The life span of T. Rhombus was estimated to be about 1 yr; males and females matured at age 6 to 8 mo. T. Rhombus is one of the fastest-growing squids: by age 300 d, they reached 750 to 800 mm ML and 17 to 17.5 kg body weight (BW). The increase in both ML and BW during ontogenesis was best fitted by a logistic growth curve. T. Rhombus has high potential fecundity (up to 4.8 million oocytes), but a rather small maximum volume of oviducts (up to 140 000 eggs) and egg masses (35 000 to 75 000 eggs). It is suggested that T. Rhombus is an intermittent spawner with multiple filling and evacuation of oviducts. The main function of the (for squid) unusual behaviour of T. Rhombus, i.e. living in pairs consisting of a male and female, is reproduction and is optimal given the low density of T, Rhombus populations and low active movement of squids

  • Structure of the reproductive system of the squid Thysanoteuthis Rhombus (Cephalopoda: Oegopsida)
    Journal of Zoology, 1991
    Co-Authors: Chingis M. Nigmatullin, Alexander I. Arkhipkin, Rushan M. Sabirov
    Abstract:

    The structure of the reproductive systems of mature males and females of the nektonic, oceanic squid Thysanoteuthis Rhombus are described. The main peculiarities of the female system are relatively low capacity oviducts, set in a tight spiral, and hypertrophically developed oviducal glands with a very large second section. The male reproductive system is characterized by a long, narrow Needham's sac containing 10–15 large spermatophores 80–100 mm in length. The mesentery supporting the gonad, and protruding into it dorsally, is a characteristic feature in both sexes. The hectocotylus structure differs markedly from that in other squids and resembles that of sepiids. The reproductive system of T. Rhombus possesses primitive features (pattern of gonad attachment and hectocotylus) but mostly secondary characters (small oviducts, very large oviducal glands and ovary). The complex morpho-ecological adaptations of T. Rhombus are reflected in the distinctive features of the reproductive system.

Alexander I. Arkhipkin - One of the best experts on this subject based on the ideXlab platform.

  • Age, growth and reproductive biology of diamond-shaped squid Thysanoteuthis Rhombus (Oegopsida : Thysanoteuthidae)
    Marine Ecology Progress Series, 1995
    Co-Authors: Chingis M. Nigmatullin, Alexander I. Arkhipkin
    Abstract:

    Age and growth of the large oceanic squid Thysanoteuthis Rhombus were estimated by statolith increment analysis of 72 specimens [mantle length (ML) ranging from 25 to 805 mm] and reproductive biology was studied on 162 T. Rhombus (ML 150 to 850 mm) captured in the eastern tropical Atlantic and southwestern Pacific between 1976 and 1990. The maximum ages found in our samples were observed in a mature female of 750 mm ML (305 d) and in a mature male of 770 mm ML (309 d). The life span of T. Rhombus was estimated to be about 1 yr; males and females matured at age 6 to 8 mo. T. Rhombus is one of the fastest-growing squids: by age 300 d, they reached 750 to 800 mm ML and 17 to 17.5 kg body weight (BW). The increase in both ML and BW during ontogenesis was best fitted by a logistic growth curve. T. Rhombus has high potential fecundity (up to 4.8 million oocytes), but a rather small maximum volume of oviducts (up to 140 000 eggs) and egg masses (35 000 to 75 000 eggs). It is suggested that T. Rhombus is an intermittent spawner with multiple filling and evacuation of oviducts. The main function of the (for squid) unusual behaviour of T. Rhombus, i.e. living in pairs consisting of a male and female, is reproduction and is optimal given the low density of T, Rhombus populations and low active movement of squids

  • Structure of the reproductive system of the squid Thysanoteuthis Rhombus (Cephalopoda: Oegopsida)
    Journal of Zoology, 1991
    Co-Authors: Chingis M. Nigmatullin, Alexander I. Arkhipkin, Rushan M. Sabirov
    Abstract:

    The structure of the reproductive systems of mature males and females of the nektonic, oceanic squid Thysanoteuthis Rhombus are described. The main peculiarities of the female system are relatively low capacity oviducts, set in a tight spiral, and hypertrophically developed oviducal glands with a very large second section. The male reproductive system is characterized by a long, narrow Needham's sac containing 10–15 large spermatophores 80–100 mm in length. The mesentery supporting the gonad, and protruding into it dorsally, is a characteristic feature in both sexes. The hectocotylus structure differs markedly from that in other squids and resembles that of sepiids. The reproductive system of T. Rhombus possesses primitive features (pattern of gonad attachment and hectocotylus) but mostly secondary characters (small oviducts, very large oviducal glands and ovary). The complex morpho-ecological adaptations of T. Rhombus are reflected in the distinctive features of the reproductive system.

Rushan M. Sabirov - One of the best experts on this subject based on the ideXlab platform.

  • Structure of the reproductive system of the squid Thysanoteuthis Rhombus (Cephalopoda: Oegopsida)
    Journal of Zoology, 1991
    Co-Authors: Chingis M. Nigmatullin, Alexander I. Arkhipkin, Rushan M. Sabirov
    Abstract:

    The structure of the reproductive systems of mature males and females of the nektonic, oceanic squid Thysanoteuthis Rhombus are described. The main peculiarities of the female system are relatively low capacity oviducts, set in a tight spiral, and hypertrophically developed oviducal glands with a very large second section. The male reproductive system is characterized by a long, narrow Needham's sac containing 10–15 large spermatophores 80–100 mm in length. The mesentery supporting the gonad, and protruding into it dorsally, is a characteristic feature in both sexes. The hectocotylus structure differs markedly from that in other squids and resembles that of sepiids. The reproductive system of T. Rhombus possesses primitive features (pattern of gonad attachment and hectocotylus) but mostly secondary characters (small oviducts, very large oviducal glands and ovary). The complex morpho-ecological adaptations of T. Rhombus are reflected in the distinctive features of the reproductive system.

Éric Rémila - One of the best experts on this subject based on the ideXlab platform.

  • Distances on Rhombus tilings
    Theoretical Computer Science, 2011
    Co-Authors: Olivier Bodini, Thomas Fernique, Michael Rao, Éric Rémila
    Abstract:

    The Rhombus tilings of a simply connected domain of the Euclidean plane are known to form a flip-connected space (a flip is the elementary operation on Rhombus tilings which rotates 180° a hexagon made of three rhombi). Motivated by the study of a quasicrystal growth model, we are here interested in better understanding how “tight” Rhombus tiling spaces are flip-connected. We introduce a lower bound (Hamming-distance) on the minimal number of flips to link two tilings (flip-distance), and we investigate whether it is sharp. The answer depends on the number nn of different edge directions in the tiling: positive for n=3 (dimer tilings) or n=4 (octagonal tilings), but possibly negative for n=5 (decagonal tilings) or greater values of n. A standard proof is provided for the n=3 and n=4 cases, while the complexity of the n=5 case led to a computer-assisted proof (whose main result can however be easily checked manually).

  • A Characterization of Flip-accessibility for Rhombus Tilings of the Whole Plane
    Information and Computation, 2008
    Co-Authors: Olivier Bodini, Thomas Fernique, Éric Rémila
    Abstract:

    It is known that any two Rhombus tilings of a polygon are flip-accessible, that is, linked by a finite sequence of local transformations called flips. This paper considers flip-accessibility for Rhombus tilings of the whole plane, asking whether any two of them are linked by a possibly infinite sequence of flips. The answer turning out to depend on tilings, a characterization of flip-accessibility is provided. This yields, for example, that any tiling by Penrose tiles is flip-accessible from a Penrose tiling.

  • LATA - A characterization of flip-accessibility for Rhombus tilings of the whole plane
    2008
    Co-Authors: Olivier Bodini, Thomas Fernique, Éric Rémila
    Abstract:

    It is known that any two Rhombus tilings of a polygon are flip-accessible, that is, linked by a finite sequence of local transformations called flips. This paper considers flip-accessibility for Rhombus tilings of the whole plane, asking whether any two of them are linked by a possibly infinite sequence of flips. The answer turning out to depend on tilings, a characterization of flip-accessibility is provided. This yields, for example, that any tiling by Penrose tiles is flip-accessible from a Penrose tiling.

  • A characterization of flip-accessibility for Rhombus tilings of the whole plane
    Information and Computation, 2008
    Co-Authors: Olivier Bodini, Thomas Fernique, Éric Rémila
    Abstract:

    International audienceIt is known that any two Rhombus tilings of a polygon are flip-accessible, that is, linked by a finite sequence of local transformations called flips. This paper considers flip-accessibility for Rhombus tilings of the whole plane, asking whether any two of them are linked by a possibly infinite sequence of flips. The answer turning out to depend on tilings, a characterization of flip-accessibility is provided. This yields, for example, that any tiling by Penrose tiles is flip-accessible from a Penrose tiling

  • A Characterization of Flip-Accessibility for Rhombus Tilings of the Whole Plane
    2007
    Co-Authors: Olivier Bodini, Thomas Fernique, Éric Rémila
    Abstract:

    It is known that any two Rhombus tilings of a polygon are flip-accessible, \emph{i.e.} linked by a finite sequence of local transformations called flips. This paper considers flip-accessibility for Rhombus tilings of the \emph{whole plane}, asking whether any two of them are linked by a \emph{possibly infinite} sequence of flips. The answer turning out to depend on tilings, a \emph{characterization} of flip-accessibility is provided. This yields, for example, that any tiling by Penrose tiles is flip-accessible from a Penrose tiling.

Baibiao Huang - One of the best experts on this subject based on the ideXlab platform.

  • synthesis morphology and phase transition of the zinc molybdates znmoo4 0 8h2o α znmoo4 znmoo4 by hydrothermal method
    Journal of Crystal Growth, 2010
    Co-Authors: Gaoke Zhang, Yanqing Yang, Wei Jiang, Shuiming Zhang, Baibiao Huang
    Abstract:

    Abstract ZnMoO 4 with a Rhombus sheet or flower-like structure, α-ZnMoO 4 and needle-like ZnMoO 4 ·0.8 H 2 O were successfully synthesized by simple hydrothermal crystallization processes with citric acid. ZnMoO 4 ·0.8 H 2 O was easily synthesized in a shorter reaction time (2 h) at a higher reactant concentration. It gradually transformed into ZnMoO 4 with a monoclinic wolframite tungstate structure with an increased reaction time, and pure ZnMoO 4 was obtained with a longer reaction time (8 h). Citric acid (CA) played an important role in controlling the morphology of the as-obtained molybdates. The α-ZnMoO 4 and ZnMoO 4 were synthesized by heating ZnMoO 4 ·0.8 H 2 O at 130 °C for 4 h and 8 h, respectively, under hydrothermal conditions. With transforming of ZnMoO 4 ·0.8 H 2 O to α-ZnMoO 4 and further to ZnMoO 4 , the needle-like crystals gradually disappeared and were transformed into crystals with Rhombus sheet morphology and then further to pentacle or flower-like crystals that can be ascribed to continuous splitting and growing of the Rhombus sheets.

  • Synthesis, morphology and phase transition of the zinc molybdates ZnMoO4·0.8H2O/α-ZnMoO4/ZnMoO4 by hydrothermal method
    Journal of Crystal Growth, 2010
    Co-Authors: Gaoke Zhang, Yanqing Yang, Wei Jiang, Shuiming Zhang, Shujie Yu, Baibiao Huang
    Abstract:

    Abstract ZnMoO 4 with a Rhombus sheet or flower-like structure, α-ZnMoO 4 and needle-like ZnMoO 4 ·0.8 H 2 O were successfully synthesized by simple hydrothermal crystallization processes with citric acid. ZnMoO 4 ·0.8 H 2 O was easily synthesized in a shorter reaction time (2 h) at a higher reactant concentration. It gradually transformed into ZnMoO 4 with a monoclinic wolframite tungstate structure with an increased reaction time, and pure ZnMoO 4 was obtained with a longer reaction time (8 h). Citric acid (CA) played an important role in controlling the morphology of the as-obtained molybdates. The α-ZnMoO 4 and ZnMoO 4 were synthesized by heating ZnMoO 4 ·0.8 H 2 O at 130 °C for 4 h and 8 h, respectively, under hydrothermal conditions. With transforming of ZnMoO 4 ·0.8 H 2 O to α-ZnMoO 4 and further to ZnMoO 4 , the needle-like crystals gradually disappeared and were transformed into crystals with Rhombus sheet morphology and then further to pentacle or flower-like crystals that can be ascribed to continuous splitting and growing of the Rhombus sheets.